Valve operator

Abstract

A valve operating machine has a reversable motor and a drive assembly for turning the stem of a valve, and a sensor for determining the torque applied to the valve stem. The amount of torque applied to the valve stem is regulated so as not to exceed the torque limits of the valve. The machine will gradually apply greater amounts of torque in opposite directions until the valve has become unfrozen. Thereafter, the valve will be rotated until the opening or closing cycle has been completed. When an increase in torque is detected, the machine will reverse to unjam a valve, and where such reversal does not result in further forward movement, the machine will terminate the cycle.

What is claimed: 
     
       1. A valve operating machine comprising in combination: drive means for turning the stem of a valve;   means for connecting and disconnecting said drive means to the stem of a first valve or a second valve;   motor means for rotating said drive means;   control means for controlling the application of torque by said motor means to said drive means;   first sensor means for measuring torque applied by said motor means to said drive means; and   computer means responsive to said first sensor means for controlling said control means to limit the application of torque to the valve stem of the connected valve such that the torque applied to the connected valve is limited to a predetermined value.   
     
     
       2. A valve operating machine in accordance with claim 1 further comprising reverse means for reversing the direction of said drive means; and said reversing means responsive to said computer means for reversing said drive means.   
     
     
       3. A valve operating machine in accordance with claim 2 wherein said computer further includes means for directing said control means to apply a predetermined torque to a non-rotating valve stem in a first direction, and then to apply said predetermined torque to said valve in a second direction. 
     
     
       4. A valve operating machine in accordance with claim 1 wherein said computer further includes means for reversing the direction of rotation for a short angular distance in response to said sensor means detecting of a first increased application of torque, and after said reversal for said short angular distance, returning to rotation in said first direction. 
     
     
       5. A valve operating machine in accordance with claim 4 wherein said computer further includes means for terminating further rotation upon said sensor means detecting a second increased application of torque at the same angular position of rotation as said first increased application of torque. 
     
     
       6. The valve operating machine in accordance with claim 1 further comprising second sensor means for sensing the rotation of said drive means in a first direction, and   said computer means responsive to said second sensor means.   
     
     
       7. The valve operating machine in accordance with claim 1 further comprising: second sensor means for sensing rotation of said drive means in a first direction and in a second direction, and   said computer means responsive to said second sensor means.   
     
     
       8. The valve operating machine in accordance with claim 1 wherein said computer means includes memory means and feedback means for retaining and recalling operating characteristics of a given valve. 
     
     
       9. The valve operating machine in accordance with claim 1 and further comprising readout means for displaying information to an operating technician. 
     
     
       10. The valve operating machine in accordance with claim 1 and further comprising a key pad for inserting instructions into said computer means. 
     
     
       11. The valve operating machine in accordance with claim 1 wherein said predetermined value of torque applied in a first direction is a varying precalculated torque value. 
     
     
       12. A valve operating machine comprising in combination: drive means for turning the stem of a valve;   means for connecting and disconnecting said drive means to the stem of a first valve or a second valve;   motor means for rotating said drive means;   sensor means for measuring the rotation of said drive means;   control means for controlling said motor means to rotate a stem of a connected valve in a first direction, and   computer means responsive to said sensor means for directing said control means to rotate a stem of a connected valve a predetermined angular distance in said first direction.   
     
     
       13. A valve operating machine in accordance with claim 12 wherein said computer means records the direction of rotation of said drive means.